Rotary compressor



March 27, 1956 LAMBERTON 2,739,758

ROTARY COMPRESSOR Filed March 23, 1955 4 Sheets-Sheet 1 INVENTOR.

- RALPH E. LAMBERTON M, y- M A TORNEYS March 27, 1956 R. E. LAMBERTON 2,739,758

ROTARY COMPRESSOR Filed March 23, 1955 4 Sheets-Sheet 2 INVEN TOR.

RALPH E. LAMBERTO N ATTORNEYS March 27, 1956 R. E. LAMBERTON ROTARY COMPRESSOR Filed March 2a, 1955 4 Sheets-Sheet 3 INVENTOR. RALPH E. LAMBERTON BY M,M, ,L

ATTORNEYS March 27, 1956 R. E. LAMBERTON 2,739,758

ROTARY COMPRESSOR Filed March 23, 1955 4 Sheets-Sheet 4 5 INVENTOR.

RALPH E. LAMBERTON M f M AT TORNEYS United StatesPatent "O ROTARY COMPRESSOR Ralph E. Lamberton, Worthington, Ohio, assignor to The Jaeger Machine Company, Columbus, Ohio, a corporation of Ohio Application March 23, 1955, Serial No. 496,199

10 Claims. (Cl. 230-207) My invention relates to a rotary compressor.

The main object of my invention is to provide a rotary compressor with means for preventing the accumulation of excessive amounts of oil in lower portions of the compressor, which might cause damage to the compressor structure.

In the accompanying drawings, I have illustrated examples of my invention, but it is to be understood that other variations of my invention are possible without departing from the basic principles thereof. In these drawings:

Figure 1 is a side elevational view of a rotary compressor having one form of my invention embodied therein.

Figure 2 is a diagram showing oil line connections to the air receiver and oil separator of the compressor.

Figure 3 is a similar view, but showing the oil lines connected to the air receiver and the oil tank of the compressor.

Figure 4 is a longitudinal sectional view taken through the cylinders and associated parts of the compressor.

Figure 5 is a transverse sectional view taken along line 5-5 of Figure 4 through the low pressure cylinder of the compressor.

Figure 6 is a transverse sectional view taken along line 66 of Figure 4 through the high pressure cylinder of the compressor.

Figure 7 is a view similar to Figure l but showing a different arrangement of my invention.

In Figure l l have illustrated a compressor of the portable type to which my invention is especially applicable although it is not limited thereto. The compressor unit itself is of the rotary type and is driven by an engine 10 which is preferably of the internal combustion type. The compressor unit itself includes the low pressure cylinder 11 and the high pressure cylinder 12. These cylinders are connected together by a manifold 13 so that low-pressure air discharged from the cylinder 11 will be conducted into the cylinder 12 for further compression.

Details of the compressor unit itself are illustrated in Figures 4 to 6. The low-pressure cylinder 11 (Figure 4) houses the rotor 14 which is coupled to and is driven by the engine 10 (Figure 1). The rotor 14 is coupled to and drives the rotor 15 which is housed in the high pressure cylinder 12. The low-pressure cylinder is provided with the valve-controlled air inlet 16 which includes the filter 17. The high pressure cylinder 12 (Figure l) is provided with a discharge outlet which connects by a discharge line 18 to the air receiver tank 13. Disposed below the tank 19 and connected thereto is the oil tank 20 and disposed above the tank 19 and connected thereto is the oil separator 21.

When the compressor is operating, air is drawn into the low-pressure cylinder 11 through the air filter 17. After compression in the low pressure cylinder 11, the air flows through the manifold 13 to the high pressure v 2,739,758 Patented Mar. 27, 1956 cylinder 12. The air is further compressed in this high pressure cylinder and is then discharged through the line 18 into the air receiver tank 19.

To provide lubrication for the cylinders 11 and 12, oil is pumped through the rotor bearings into each end of each cylinder. This is indicated diagrammatically in Figure l where the dotted line passageway 22 indicates symbolically the passageways and oil galleries extending through the compressor to conduct the oil to the rotor bearings. Oil is also sprayed into the respective cylinders through openings along the sides of the cylinders. Thus, the opening 23 in Figure 5 serves as the means for spraying oil into the low-pressure cylinder 11 and the opening 24 in Figure 6 serves as the means for spraying oil into the high pressure cylinder 12. The openings 23 and 24 are connected (not shown) to the passageway 22 (Figure 1) which, in turn, is connected to a lubrication pump 25 which is coupled to the high pressure rotor 15 so that it is driven thereby. This pump may be an oil gear type or any other suitable type. The oil supplied to the various parts by the pressure system described above serves as a lubricant, a sealing agent, and for cooling. The oil supplied to the lowpressure cylinder 11 passes therefrom, with the air compressed therein, through the manifold 13 to the high pressure cylinder 12. This air, bearing a supply of oil, is further compressed in the cylinder 12 and is discharged into the air receiver 19. Thus, substantially all oil supplied to each cylinder 11 and 12 is carried along by the velocity of the air.

Most of the oil in the air which is supplied to the air receiver 19 will drop to the bottom of the receiver as it flows thereinto. This oil will be collected in the tank 20. The compressed air flows from the receiver 19 into the separator 21 and any oil vapors remaining in the air are retained by the filtering elements in the oil separator so that air discharged from the separator is substantially oil-free and is ready for use. However, means is provided at the bottom of the outlet of the oil separator to drain out any oil that may bypass the filtering elements. This means includes a drain line 26 that is connected to the end of the low-pressure discharge manifold 13 as indicated at 27 in Figure 1. A check valve 1 28 is provided in the line 26 so oil-laden air will not be forced up into the discharge end of the oil separator when the compressor is started. As soon as air pressure in the discharge end of the oil separator exceeds the pressure in the low-pressure manifold 13, any oil that may pass through the filters of the separator 21 will flow back into the low-pressure manifold 13. i

Air pressure in the receiver 19 forces oil that collects in the tank 20 through a line 29 connected thereto to an oil cooler 30 which is located ahead of the water radiator 31 of the engine 10. From the cooler 30, the oil is carried through a line 32 to the oil pump 25. The oil pump 25, as previously indicated, forces this oil through the various conducting passageways and galleries indicated by the line 22. This pump 25 delivers the cooled and filtered oil to the compressor cylinders 11 and 12 at the proper pressure.

During normal operation of the compressor, all oil passing from the low-pressure cylinder 11 with the air will pass into the high pressure cylinder 12 and out to the air receiver 19.

If the compressor runs for long periods unloaded, it might be possible for an excessive amount of oil to accumulate in the low-pressure manifold 13. If this should take place prior to a sudden air demand equal to the full capacity of the compressor, the compressor will instantly accelerate to full speed, sucking in a large volume of oil into the high pressure cylinder 12, causing a hydraulic jam between the vanes of the rotor 15. Such an accumulation of oil could damage or break the vanes.

Also, when the air compressor is used for pipe line work on very irregular terrain the compressor may be operating at very steep angles which could possibly cause an excessive accumulation of oil in the lowest end of the high pressure cylinder 12 with a resulting serious damage or breakage of the vanes of the rotor 15 in the high pressure cylinder.

To overcome these possibilities, a second oil pump which will serve as a sump or scavenging pump, is provided to pump .oil from the low-pressure discharge manifold 13 or air inlet cavity of the high pressure cylinder 12. The discharge of this pump will be connected to the air receiver 19 or to the oil tank 20.

Thus, as shown in Figure 1 a second pump 33 is provided which may be of the oil gear type or other suitable type. This pump is driven direct from the crankshaft of the engine 10. The inlet line 34 of this pump is connected to the bottom side of the manifold 13, as shown at 35 in Figure 5, or to the air inlet cavity of the high pressure cylinder as shown at 35a in Figure 6. The outlet line 36 of this pump is connected either to the air receiver 19, as shown at 37 in Figure 2, or to the oil storage tank, as shown at 37a in Figure 3. Thus, with both arrangements, any oil which tends to accumulate in the manifold 13 or the lower portion of the cylinder 12 will be withdrawn immediately by the sump or scavenging pump 33 and will be returned to the air receiver 19 or to the oil tank 20.

As an alternate arrangement a double oil pump can be provided at the outer end of the high pressure cylinder as shown in Figure 7. One section 250 of this oil pump will lubricate the air compressor and the other section 33a of this oil'pump will serve as an oil sump or scavenging pump to prevent an excessive oil accumulation from the low-pressure cylinder 11a.

In this instance the line leading to the pump section 25a is indicated by the numeral 32a and the passages leading therefrom to the various parts of the compressors are indicated at 22a. The line leading from the manifold 13a or high pressure cylinder 12a to the scavenging pump 33a is indicated at 34a and the line leading from the pump 33a to the oil tank a or to the receiver 19a is indicated at 35a. The sections a and 33a of the pump are independent insofar as fluid pressure is concerned, but are coupled together and to the rotor of the high pressure cylinder so that they are both driven thereby. This arrangement of Figure 7 will function in the same manner as the one shown in Figure 1, to prevent an accumulation of excess oil in the manifold 13a and in the lower portion of the high pressure cylinder 120.

It will be apparent from the above description that I have provided simple yet efiective arrangements for preventing the accumulation of excessive amounts-of oil 'in the lower portions of the manifold and in the high pressure cylinder.

Having thus described my invention, what I claim is:

l. A rotary compressor comprising a low-pressure cylinder, a high-pressure cylinder, arnanifold connecting the discharge of the low-pressure cylinder to the inlet of the high-pressure cylinder, a lubricant-supplying pressure system connected to the low-pressure cylinder, and a scavenging pump having its inlet connected at the inlet side of said high-pressure cylinder to prevent the accumulation of excessive amounts of lubricant in the lower part of the high-pressure cylinder and the lower part of said manifold.

2. The combination of claim 1 in which said pressure system comprises a lubricating pump with its outlet connected to said low-pressure cylinder, and said scavenging pump has its inlet connected to the manifold and the highpressure cylinder.

3. The combination of claim 2 in which the inlet of the scavenging pump is connected to the lowest part of the manifold.

4. The combination of claim 1 in which the inlet of the scavening pump is connected to the lowest part of the high-pressure cylinder.

5. The combination of claim 1 in which the outlet of the scavenging pump is connected to the discharge side of the compressor beyond the outlet of the high-pressure cylinder.

6. The combination of claim 5 in which the outlet of the scavenging pump is connected to the air receiver which receives the compressed air discharged from the highpressure cylinder.

7. The combination of claim 5 in which the outlet of the scavenging pump is connected to the oil storage tank that is connected to the air receiver.

8. The combination of claim 1 in which the scavenging pump is coupled to the high-pressure rotor and is driven thereby.

9. The combination of claim 8 in which the lubricating pump and scavenging pump are combined as a double pump having sections which are coupled together for driving but are independent as to fluid pressure operation.

10. The combination of claim 1 in which the compressor is driven by an engine, said lubricating pump is coupled to the high-pressure rotor and is driven thereby, and said scavenging pump is driven directly by said engine.

References Cited in the file of this patent UNITED STATES PATENTS 

